The purpose of this study will be to isolate and characterize the major basic proteins of peripheral nerve myelin and determine their immunogenic properties especially with regard to their ability to produce experimental allergic neuritis in Lewis rats. By isolating immunogenic peptide fragments, we will localize the antigenic and neuritogenic determinants and investigate the properties of these determinants. Using the P2 protein or peptides we will attempt to manipulate the immune response so as to affect and particularly to treat the disorder. We will study the circulating antibody response and cell-mediated immune response to the neuritogenic determinants during the induction and treatment of experimental allergic neuritis. Since experimental allergic neuritis is the appropriate model for human idiopathic polyneuritis, we hope to gain insight into the nature of the human disease so as to design more effective treatment for this condition.